Protracting device.



No. 717,920. PATBNTED JAN. 1903.

A. s. PRALL PROTRAGTING DEVICE.

APPLICATION FILED FEB. 13, 1902.

Z SHEETS-SHEET 1.

H0 MODEL.

WITNESSES. INVE/VTUI? I flrviz'igyfifj i'all.

' My ATTORNEY.

1 No. 717,920. PATENTED JAN. 6, 1903.

A. s. PRALL. PROTRAGTING DEVICE.

APPLICATION FILED FEB. 13, 1902.

N0 MODEL. 2 SHEET-SHEET 2.

. EET a cmuus lb EEG-L I EFIEFIEE' NITED STATES PATENT OFFICE.

ANNINGA s. PRALLLOF Pour RICHMOND, NEW YORK.

PROTRACTING DEVICE.

SPECIFICATION forming part of Letters Patent No. 717,920, dated January 6, 1903.

Application filed February 13, 1902. Serial No. 93,975. (No model.)

T0 all whom, it may concern:

Be it known that I, ANN-ING S. PRALL, a citizen of the United States, and a resident .of Port Richmond,in the countyof Richmond and State of New York, have invented certain new and useful Improvements in Protracting Devices, of which the following is a specification.

My invention, while relating to protracting devices generally, is designed more especially for use in plotting tracts and lots of land in books or on sheets of paper or other appropriate materials, its object being to provide a device of this character which, in

addition to being simple and cheap in construction, shall at the same time permit of the plotting of lots or tracts of lands or other forms upon materials that are more or less opaque and that, too, without the aid of paper or other material that is of a transparent character.

To this end the invention consists of a suitable table and a graduated protractor, with an appropriate indicator and scale, all as will be hereinafter more fully set forth.

Referring to the accompanying drawings, which form a part of this specification, Figure 1 is a plan view of a protracting device constructed in accordance with my invention and showing by full and dotted lines the manner of usingthe same; Figs 2 and 3, similar views of the device, showing also by full and dotted lines the mannor of using the same, with portions of the table and the protractor of each broken away for convenience ofillustration'; Fig. 4, a vertical section of a portion of the device, taken in the plane w to in Fig. 1; Fig. 5, a similar vertical section of a portion of the same, taken in the plane y y in Fig. 1; and Fig. 6, a face view of the scale detached.

In all the figures like letters of reference are employed to designate corresponding parts.

A indicates a table upon which the plotting is effected, the same being constructed of wood or other appropriate material in plate form andof the required thickness to suit it to the uses for which it is intended. I prefer, however, to construct it of wood and in approximately rectangular contour, with its several angles or corners rounded m off, and to strengthen the same and prevent it when made as a complete circle, is preferably,

though not necessarily, divided into quadrants, which are separated from one another 7 by the respective letters N E W S and the numbering of the degrees of each quadrant commenced with a new series of figures.

Cooperating with the protractor Bis an indicator O, by means of which the center of the protractor may be indicated when the same is covered by the paper or other article on or in which the protraction is to be made. This indicator is preferably pivoted to the table A outside of the periphery of the protractor in a stand D, which is secured to the upper surface of the former by screws 0. As thus arranged the indicator may be swung upward into a vertical position, as shown by dotted lines in Fig. 4, when it is desired to superpose a sheet of paper or other article upon the protractor or otherwise or downward into an approximately horizontal p0sition, with its point resting upon the sheet or other article directly over the center of the protractor, as shown by full lines in that figure. With the protractor and indicator thus described is employed a ruler or scale E, which may he graduated with any appropriate units of measure or otherwise, as may be desired. In the form shown in the drawings, however, which is the one I prefer in practice, the scale is divided into chains and feet units, which are or may be appropriately numbered along the scale, as is common to scales and rules ordinarily in use, and forms no part of my present invention.

The various parts being constructed as above described and a sheet of paper or other article F resting upon the protractor, with the indicator turned downward and its point resting thereon directly over the center of the latter, the protraction of any plot or figure upon such sheet or article will be effected as follows: Assuming that the figure to be plotted is approximately rectangularin form and that the first line is to be drawn to represent a length of three hundred feet running north by sixty degrees east, the second two hundred feet running south by thirty degrees east, the third three hundred feet running south by sixty degrees west, and the fourth two hundred feet running north by thirty degrees west, the scale E will be placed upon the paper or other article F on or in which the figure is to be plotted,with its edge against the downturned end of the indicator 0 opposite the zero-mark upon itself and in line with the sixtieth degree of the quadrant between the letters N and E, and the first line will be drawn with a pencil or other marker along the edge of the scale from the point e to the point'f or from the zero-line to thelinemarked 300 thereon. Withthe scale still held in this position against the indicator and in line with the sixtieth degree of such quadrant the paper or other article will be moved from the position shown by full lines in Fig. 1 into the position shown by dotted lines in that figure, by which the end f of the line thus drawn will be brought beneath the downturned end of the indicator, and the line itself will extend on the opposite side of that point along the edge of the scale, as shown by dotted lines in that figure. With the paper moved into this position the scale will be turned around the point of the indicator, while its edge is held in contact therewith opposite its zero-mark until this edge is brought into line with the thirtieth degree of the quadrant between E and S, when the second line will be drawn along the edge of the scale from the point f to the point g or from the zero-mark to the mark indicated by 200 upon the same. In this posit-ion the scale will be held and the paper or other article in or on which the protraction is being made moved under the same from the position shown in full lines in Fig. 2 to that shown by dotted lines in that figure, when the termination g of the line last drawn will be brought opposite the zero-mark on the scale and beneath the indicator, and the line itself will extend on the opposite side of that point along the edge of the scale, as shown by dotted lines in that figure. The scale will then be turned around the indicator-point, while its edge opposite the zero-mark is held against the same, until its edge comes opposite the sixtieth graduation of the quadrant S and W, when the third line will be drawn from the point 9 to the point It, or from the zero-mark on the scale to that indicated by 300 thereon. Upon the completion of this line the sheet or other article will be moved along under the scale and indicatorpoint from the position shown by full lines in Fig. 3 to the position shown by dotted lines in that figure, when the termination h of this line will be brought beneath the indicatorpoint and the line itself carried on the opposite side of the same, as shown by dotted lines in the last-mentioned figure. The movement of the paper or other article being thus completed, a further rotation of the scale about the indicator, with its edge opposite the zero-mark in contact therewith, will be made until its edge is brought into line with the thirtieth graduation of the quadrant between N and W, when the fourth line of the figure will be drawn along its edge from the point h to the point e, or from the zero-mark to the two-hundredth mark and the figure completed, and so on, the scale serving to indicate the lengths of the several lines and the protractor to measure their angular relationship.

From the foregoing, therefore, it will be seen thatI provide a protracting device which is not only simple and cheap in construction, but admirably suited to the plotting of lots or tracts of land on sheets of paper or other material and in books, as well as to the drafting and drawing of other figures where the length of the sides and their angular relationships are to be indicated.

While in the foregoing I have described the form of apparatus which I prefer to employ in practice, I wish it distinctly understood that I do not limit myself strictly thereto, as it is obvious that it may be modified in various ways and still be within the scope of the invention.

Having now described my invention and specified the best means contemplated by me for carrying it into practice, I claim and desire to secure by Letters Patent of the United States 1. The combination, with a table upon which the plotting may be effected provided with a protractor, of an indicator provided with a downwardly-extending point for indicating the center of the protractor, and means for supporting the said indicator and permitting of it being moved toward and away from the protractor, the supporting means being located at a fixed point with respect to the center of the protracter, substantially as described.

2. The combination with a table upon which plotting may be effected provided with a protractor, of an indicator provided with a downwardly-extending point for indicating the center of the protractor, and supporting means for said indicator, the supporting means being located at a fixed point with respect to the center of the protractor.

3. The combination, with a table provided with a protractor on its upper side, of an indicator provided with a downwardly-extending point for indicating the center of the protractor, hinged to the table outside of the protractor at a fixed point relatively to the center of the protractor whereby to be capable of being swung upward away from and downward toward such protractor, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ANNING S. PRALL.

WVitnesses:

GEORGE F. OoHs, WILLIAM ROBERTS. 

